I can tell you the last known discovered Athens NewStyle issue that was identified,new obverses and especially reverses varieties are commonish, but what about the Roman denarius-preferably a proper silver type. Or was it all over about a century and a half or more ago?
Are you asking when was the last time a new denarius type was discovered? New types and varieties are discovered all the time - I believe Pescennius Niger is a particular hot spot for new varieties and types as his coinage seems to have been largely destroyed, making many individual coins the first known type of an emission that would have been large in 193 or 194. A search for "denarius+unpublished" returns 424 hits on ACSearch, obviously not all of them actual denarii. https://www.acsearch.info/search.ht...s=1&thesaurus=1&order=0¤cy=usd&company=
good questiion..well, for a 'proper' denarius, i'd say 3rd century, around the time of Severus Alexander..or not too much afterwards i'd reckon (but i could be wrong )
Well, theoretically you are wrong because, even after Gordian III, the denarius continued to be struck in very small quantities until Diocletian's coinage reform replaced it. Anyways, as @Finn235 said, every now and then new varieties of denarii are found, almost always of Pescennius Niger or of other emperors' eastern mints; I'm not knowledgeable enough in this field to tell you the specific types in detail, but usually it comes down to differences in the legends.
...i'm from Missouri......i can't find it in my file at the moment, but the last denarius of good silver in my collection is of Elagalabus..
Good silver yes, debased billion no. I posted a thread https://www.cointalk.com/threads/the-last-denarius.370876/ Where I posted just about the last reasonably circulating denarius
I don't have an Aurelian (or Severina) AE denarius, but I have a couple GIII denarii I'll share again.